Recent research on human (Dawson, Maida and Rubin, 1981) and cat eyes (Maffei and Fiorentini, 1981) leaves little doubt that the corneal potentials elicited by small angle subtense patterns are wholly or largely the consequence of activation of retinal ganglion cell layers. In order to obtain quantitative data on numerical and spatial relations between cells and signal we will utilize rhesus monkeys with multiple laser lesions of the peripapillary optic nerve axons for the production of varied degenerations of the ganglion cell layer. Emphasis will be made on the relation of the corneally derived pattern evoked retinal response (PERR) to (a) varing the regions of degeneration of approximately equal cell loss, (b) varing the extent of cell loss, (c) temporal relationships between degenerative change and the onset of detectable functional (PERR) change, and (d) the correlation between ganglion cell activation (as measured by optic nerve unit PSTH analysis) and the two major types of signal analyses (signal amplitude versus power spectral density). Lesion density, extent and site will be measured by the uptake of retrograde transported HRP and also by ganglion cell body density measures obtained through classical nissl stain procedures. Future research will use this data base for the interpretation of PERR signals produced in patients with diseases of the inner retina and optic nerve. Improvement of the understanding of these corneal potentials provides for the contemplation of research on retinal "acuity" in distinction to cortical and subjective "acuity".